Short communicationSocial status and GnRH soma size in female convict cichlids (Amatitlania nigrofasciatus)

•We examine social influences on gonadotropin-releasing hormone in the hypothalamus.•Female social status affects GnRH neuron soma size in the preoptic area.•Dominant females have larger GnRH neuron soma.•We found no effects on number of GnRH neurons.

Gonadotropin-releasing hormone (GnRH) neurons in the preoptic area (POA) of the hypothalamus play a key role in regulating reproductive function. These neurons in turn are modulated by environmental influences, including the social environment. In both the Old World cichlid Astatotilapia burtoni and the New World cichlid Amatitlania nigrofasciatus, the size of the soma of GnRH expressing neurons in the POA varies with social status in males and breeding state in females. Dominant males have larger GnRH-releasing cells than subordinate males, and spawning females have larger GnRH-releasing cells than brooding females. A. nigrofasciatus is monogamous and both sexes engage in similar levels of aggression and territorial defense. Here we test whether female A. nigrofasciatus display GnRH-releasing cell plasticity as a function of dominant status. We find that GnRH-releasing neuron soma sizes are larger in dominant females and that this difference is independent of differences in gonado-somatic index in A. nigrofasciatus.